<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>11_css选择器</title>
    <style>
        /* 标签选择器一般设置一些通用样式 */
        *, html, body {
            margin: 0;
            padding: 0;
        }
        a {
            text-decoration: none;
        }
        ul, li {
            list-style: none;
        }
        #title {
            color: aqua;
        }
        /* css权重 当寻找路径越精确 权重越高 id选择器 最高 */
        .container .title {
            font-size: 30px;
            color: aquamarine;
        }
        .title {
            color: bisque;
        }
        #title:hover {
            color: blue;
            font-weight: bolder;
        
        }
        .btn {
            background-color: brown;
            color: white;
        }
        .btn:hover {
            font-size: 20px;
        }
        .btn:active {
            background-color: aquamarine;
        }
    </style>
</head>
<body>
    <div class="container">
        <div>
            <span class="title">第二层级</span>
        </div>
        <span id="title" class="title">第一层级</span>
    </div>
    <ul>
        <li>123</li>
        <li>456</li>
        <li>789</li>
    </ul>
    <a href="https://www.sina.com.cn">新浪</a>
    <span class="title">456</span>
    <span>789</span>
    <button class="btn">测试悬停和激活</button>
</body>
</html>